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Updated: Jul 19, 2025
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Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior
Published on: April 16, 2014
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Neural Representations in Visual and Parietal Cortex Differentiate between Imagined, Perceived, and Illusory
Siyi Li1, Xuemei Zeng1, Zhujun Shao1,2
1Institute of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
Summary
The brain uses the parietal cortex for internally generated visual imagery, distinguishing it from external perception. This finding was supported by studies on visual illusions, highlighting the parietal cortex's role in subjective experience.
Area of Science:
- Neuroscience
- Cognitive Science
- Psychology
Background:
- The brain must distinguish between internally generated (imagined) and externally perceived information.
- Shared neural pathways for perception and imagery raise questions about differentiating these experiences.
- Understanding this differentiation is crucial for cognitive function.
Purpose of the Study:
- To investigate the neural processes distinguishing visual imagery from perception and illusion.
- To identify brain regions involved in differentiating subjective internality and externality.
- To explore the role of the parietal cortex in internally generated experiences.
Main Methods:
- Functional magnetic resonance imaging (fMRI) to measure brain activity.
- Eye-tracking to monitor visual attention.
- Multivariate decoding and encoding to analyze neural representations.
- Comparison of voluntary imagery, veridical perception, and visual illusion.
Main Results:
- Parietal cortex showed stronger orientation representations during imagery than perception.
- Early visual cortex showed stronger representations during perception than imagery.
- Illusion representations were similar to imagery in early visual cortex and perception in parietal cortex.
- Imagery dominance developed along a posterior-to-anterior cortical hierarchy.
Conclusions:
- Parietal cortex plays a domain-general role in internally generated experiences, supporting subjective imagery.
- Content-specific representations in the parietal cortex differentiate subjective internal from external experiences.
- Findings offer insights into the neural mechanisms distinguishing imagined from perceived reality.
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